線程對(duì)象也是線程類(lèi)創(chuàng)建的，也有私有成員。這個(gè)私有成員，是線程私有的。有時(shí)候使用線程私有變量，會(huì)巧妙避免一些并發(fā)安全的問(wèn)題，提高程序的靈活性和編碼的復(fù)雜度。

/** 
* 為線程添加編號(hào)，確定創(chuàng)建過(guò)線程的數(shù)目 
* 
*/ 
public class ThreadVarTest { 
        public static void main(String[] args) { 
                Thread t1 = new MyThread(); 
                Thread t2 = new MyThread(); 
                Thread t3 = new MyThread(); 
                Thread t4 = new MyThread(); 
                t1.start(); 
                t2.start(); 
                t3.start(); 
                t4.start(); 
        } 
} 
class MyThread extends Thread { 
        private static int n = 0;    //線程數(shù) 
        private int x = 0;               //線程編號(hào) 
        MyThread() { 
                x = n++; 
        } 
        @Override 
        public void run() { 
                Thread t = Thread.currentThread(); 
                System.out.println(t.getName() + "\t" + x); 
        } 
}